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<br /> <br />1313 Sherman Street, Room 215, Denver, CO 80203 P 303.866.3567 F 303.832.8106 http://mining.state.co.us <br />John W. Hickenlooper, Governor | Robert W. Randall, Interim-Executive Director | Virginia Brannon, Director <br /> <br />1313 Sherman Street, Room 215 <br />Denver, CO 80203 <br /> <br /> <br /> <br /> <br />MEMORANDUM <br />To: Tim Cazier, DRMS <br />From: Amy Eschberger, DRMS <br />Date: October 19, 2016 <br />RE: Cresson Project, DRMS Permit No. M-1980-244, Amendment-11 Application <br />(Revision No. AM-11), Adequacy Review No. 2 of Hydrology Sections <br /> <br /> <br />The Division of Reclamation, Mining and Safety (Division) completed its review of the Responses <br />to Adequacy Review: Hydrologic Submittal received on July 28, 2016, and has identified the <br />following adequacy items which require additional clarification from the Operator. The adequacy <br />item numbers listed below correlate with the Division’s Adequacy Review of Hydrology Sections, <br />dated May 31, 2016. <br /> <br />(Volume II of IV) <br /> <br />Hydrogeochemistry Evaluation / December 15, 2015 / Adrian Brown <br /> <br />3.4.2 Water Table <br />3) The Operator’s response does not satisfy the requirements of Rules 6.4.7(2)(c), <br />6.4.21(8)(c-e), and 3.1.5(10) and (11). As discussed below, the Division requires <br />additional information regarding the hydrogeology of the area of the Eastern Volcanic <br />Overflow Apron (particularly for the ECOSA footprint), the area identified as “area <br />where drainage tunnels do not cause significant head change in diatreme” on Plate 9 <br />(Rev. 1), and the area identified as “post-mining Grassy Valley capture zone on Plate 9 <br />(Rev. 1). In the description, please include an explanation of how the groundwater <br />monitoring wells located in Grassy Valley (GVMW-8A, GVMW-8B, GVMW-22A, and <br />GVMW-22B) are adequate for identifying potential sources of groundwater <br />contamination in Grassy Valley. <br /> <br /> Please provide a cross-section oriented roughly perpendicular to the northern portion of <br />the ECOSA, displaying the features shown on Plate 9 (Rev. 1) and Plate 17 (Rev. 1), <br />including the ECOSA, the ECOSA underdrains, the Grassy Valley perched aquifer, <br />Grassy Valley Creek, the contact between the diatreme and Precambrian rocks, and the <br />portion of the area identified on Plate 9 (Rev. 1) as the “area where drainage tunnels do <br />not cause significant head change in diatreme” which underlies the ECOSA. <br />